1. Field of the Invention
The present invention relates to an optical signal transmission link, and more particular to an optical signal transmission link that exhibits a resistance to bending losses, while maintaining a large mode field diameter.
2. Technical Background
The attenuation of a light signal within an optical waveguide fiber caused by bending losses, such as macrobend loss and microbend loss, is an important consideration in the design of optical transmission systems and components, such as amplifiers, fiber optic devices, fiber optic sensors and integrated optics. While attempts have been made to design these optical transmission systems and components around bending losses, sharp bending of the associated optical fiber is inherent in some optical systems, such as amplifiers, miniature delay lines, pay-out systems, fly-by light systems, Sagnac interferometers, and other similar systems, components and environments.
Heretofore, the problems associated with bending losses in the above listed components and like systems were solved by utilizing high numerical aperture, reduced core, single mode fibers. However, these high numerical aperture single mode fibers have several drawbacks including a limited bending loss performance, significant wavelength dependency, and relatively small mode field diameters, which are incompatible with standard single mode telecommunication systems.
Therefore, it would be desirable to develop alternative optical transmission systems and associated optical transmission links that provide a high bending tolerance while maintaining relatively large mode field diameters.
The present invention meets the need for an optical transmission link that provides a high tolerance to both microbending and macrobending attenuation losses, while maintaining a relatively large mode field diameter.
One embodiment of the present invention is to provide an optical signal transmission link that includes a first single mode optical fiber for receiving an optical signal, and a graded index multimode optical fiber for receiving the optical signal from the first signal mode optical fiber. The multimode optical fiber of the transmission link is adapted to support the propagation of greater than or equal to four LP modes within a wavelength range of from about 1310 nm to about 1550 nm, has a mode field diameter of within the range of from about 3.0 xcexcm to about 14.0 xcexcm within a wavelength range of from about 1300 nm to about 1650 nm, and has a numerical aperture value of greater than or equal to about 0.16.
Another embodiment of the present invention relates to an optical signal transmission link that includes a first single mode optical fiber for receiving an optical signal, and a graded index multimode optical fiber for receiving the optical signal from the first single mode optical fiber. The multimode optical fiber of the transmission link is adapted to support the propagation of greater than or equal to 4 LP modes within a wavelength range of from about 1310 nm to about 1550 nm. The transmission link provides a bending loss of less than or equal to about 0.60 dB within a wavelength range of from about 1300 nm to about 1630 nm when 1000 loops of the multimode fiber is wrapped about a cylinder having a 2.0 mm diameter.
The present invention also includes optical communication systems employing optical signal transmission links in accordance with the embodiments described above.
The present invention utilizes a first single mode optical fiber in combination with a graded index multimode optical fiber to provide an optical signal transmission link that is highly resistant to microbend and macrobend attenuation losses, while simultaneously providing a large mode field diameter.
Additional features and advantages of the present invention will be set forth in the detailed description which follows and will be apparent to those skilled in the art from the description or recognized by practicing the invention as described in the description which follows, together with the claims and appended drawings.
It is to be understood that the foregoing description is exemplary of the invention only and is intended to provide an overview for understanding of the nature and character of the invention as it is defined by the claims. The accompanying drawings illustrate various features and embodiments of the invention, which, together with their description serve to explain the principals and operations of the invention.